Holy space-cows what a mess! One of James Pevney's relatively weak early efforts was this Halloween episode of TOS - complete with black cats, witches, zombies, skeletons, dungeons, and magic wands. In retrospect, Catspaw (especially the not-so-special effects) is laughable, but not entirely without merit. Shatner and guest stars Theo Marcuse and Antoinette Bower have some great scenes. Sadly, the very talented Marcuse passed away a month after this episode was aired. Had he lived into his 50s and 60s, he could have become the 1970s and 1980s Vincent Price.
An away team suffers a casualty and a few missing crew members, including Sulu and Scotty. The holy trinity (Kirk, Spock and McCoy) beam down to investigate. On the planet's surface, they quickly encounter a trio of ghosts, a medieval-looking castle, and a black cat. Kitty leads them to a trap and they wake up chained up in a dungeon.
Some would say this is all pure schlock, but there are a few aspects of Catspaw that make it worth seeing. As I have mentioned, some of the acting is quite good. It's also worth thinking about the ambiguity of what goes on in the episode. On one hand it comes off as just another omnipotent alien episode, but these aliens are pretty different, and its not clear how much power they really have outside of their own minds and the minds of the Enterprise crew. Unfortunately, though these ideas are raised in the episode, they are also inadequately explored in this straightforward goth adventure story.